1. Field of the Invention
The present invention relates to a test system, notably to a test system for measuring the concentration of an analyte in a biological fluid, and to a method of using the system. The system is particularly for use in long term care facilities but could also be used in other environments.
2. Description of the Prior Art
In long term care facilities such as hospitals, clinics, care homes, Infirmaries and hospices, it is frequently necessary to monitor the level of analytes such as glucose or cholesterol in a patients body to ensure that the patient is given appropriate food and/or medication. Typically, the analyte concentration is measured in a biological fluid such as a sample of the patients whole blood or urine, using a suitably-calibrated test meter. The test meter typically uses disposable test strips which contain an enzyme reagent system which is specific to a particular analyte and which produces a measurable change in reflectance or an electrochemical value such as electric current. The magnitude of the change or measured value is related to the analyte concentration in the sample. To allow a single meter to be used with different batches of test strips, each batch of test strips may be provided with a code chip which contains batch-specific calibration data. The operator (typically a physician, nurse or care assistant) inserts the code chip in the meter when a new batch of test strips is opened. Any previous code chip is discarded. The meter reads the calibration data (typically contained in a lookup table) and outputs a calibrated analyte concentration value derived from those data and the measured change or value caused by the addition of the fluid sample to the test strip.
The same meter may be used to measure different types of analyte depending on the type of test strip which it is used with. For example, one type of test strip may be used to measure blood glucose and another to measure blood cholesterol. The information about the type of test strip may be encoded in the code chip or may be entered manually by the operator.
It has been proposed in U.S. Pat. No. 5,989,917 to include in a test meter a receptacle for receiving a container of test strips, and a mechanism for reading Information about the test strips that is affixed to the container. The information may be applied to the container in the form of a machine-readable bar-code, magnetic stripe; a memory chip or as a resonant wire loop. A problem with this approach is that the meter is made bulkier by needing to accommodate the container, and switching between measuring one type of analyte and another is time consuming because of the need to remove one container and Insert another. The system also requires that the containers are of a standard size and shape, so that the meter may not be usable with all test strips.
In US 2005/0009122 A1 it is proposed to provide a test cartridge including a test medium and an RFID device that is readable by the meter and contains information useful in controlling the performance of an analyte concentration test. The cartridge may be multi-use (reusable) or single-use (disposable). Where the test cartridge is disposable (as a test strip is) incorporation of an RFID device significantly increases the manufacturing costs of a batch of test strips.
After taking an analyte measurement, the result must be logged on a computer system, together with patient-specific data such as the patient's name. Desirably, other data are also logged to provide a complete medical record trail. Such other data include the Identity of the operator, and the date and time of testing. The computer system may be interrogated by a physician or other personnel when formulating a suitable care regime for the patient.
A problem with existing systems is that recording of the various data can be time consuming, and transcription errors can lead to wrongful diagnoses or sub-optimal care regimes being instituted.